Causas De Mortalidad De Colonias De Polistes Dominula (Christ, 1791) (Hymenoptera, Vespidae) En Zonas Urbanas Del Suroeste De La Península Ibérica

Graellsia, 76(1): e109 enero-junio 2020 ISSN-L: 0367-5041 https://doi.org/10.3989/graellsia.2020.v76.261

Notas / Notes

Causes of Polistes dominula (Christ, 1791) (Hymenoptera, Vespidae) colony mortality in urban areas of the south-western Iberian Peninsula

José Luis Pérez-Bote1 & Carlos Mora-Rubio2

1,2 Departamento de Anatomía, Biología Celular y Zoología, Universidad de Extremadura, Av. de Elvas s/n, 06006 Badajoz, Spain. 1 Email: [email protected] – ORCID iD: https://orcid.org/0000-0002-4042-5391 2 Email: [email protected] – ORCID iD: https://orcid.org/0000-0002-1847-3215

ABSTRACT

From 2017 to 2018 we studied populations of the eusocial paper wasp Polistes dominula (Christ, 1791) in three municipalities of the south-western Iberian Peninsula, in order to identify the causes of colony mortality. The results showed that the first main cause of mortality in the study area was human activity (43.55 %). The second most important cause was abandonment of the nest (20.19 %). Only 82 of the 411 nests (19.95 %) showed signs of natural colony decline, following the emergence of reproductives. Keywords: Polistes dominula; Hymenoptera; Vespidae; nest mortality; urban areas; Iberian Peninsula.

RESUMEN

Causas de mortalidad de colonias de Polistes dominula (Christ, 1791) (Hymenoptera, Vespidae) en zonas urbanas del suroeste de la Península Ibérica

De 2017 a 2018 se estudiaron diversas poblaciones de la avispa eusocial Polistes dominula (Christ, 1791) en tres municipios del suroeste de la península ibérica, con la finalidad de identificar las causas de mortalidad de sus colonias. Los resultados mostraron que la causa principal de mortalidad en las zonas de estudio fue la actividad antrópica (43,55 %). La segunda causa más relevante fue el abandono del nido (20,19 %). Únicamente 82 de 411 nidos (19,95 %) demostraron un declive natural de la colonia, tras la aparición de reproductores. Palabras clave: Polistes dominula; Hymenoptera; Vespidae; mortalidad de colonias; áreas urbanas; península ibérica.

Recibido/Received: 11/12/2019; Aceptado/Accepted: 22/04/2020; Publicado en línea/Published online: 19/06/2020 Cómo citar este artículo/Citation: Pérez-Bote, J. L. & Mora-Rubio, C. 2020. Causes of Polistes dominula (Christ, 1791) (Hymenoptera, Vespidae) colony mortality in urban areas of the south-western Iberian Peninsula. Graellsia, 76(1): e109. https://doi.org/10.3989/graellsia.2020.v76.261

In the Old World, Polistes dominula (Christ, 1791) absent from the coldest parts. It is particularly abun- is without doubt one of the most abundant Polistes dant in countries around the Mediterranean basin and Latreille, 1802 species. Its distribution covers the North African countries. Polistes dominula also occurs whole of central and southern Europe, although it is in Central and South Europe as far north as Latvia, 2 Notas / Notes

Fig. 1.— Types and numbers of Polistes dominula (Christ, 1791) nest losses in 2017 (black bars) and 2018 (grey bars) (OL: Olivenza, SF: San Francisco de Olivenza, SB: San Benito de la Contienda). Fig. 1.— Causa y número de nidos de Polistes dominula (Christ, 1791) desaparecidos en 2017 (barras negras) y 2018 (barras grises) (OL: Olivenza, SF: San Francisco de Olivenza, SB: San Benito de la Contienda). but missing in Great Britain, Scandinavia, Crete and San Benito de la Contienda (38°37′59″ N, 7°09′26″ W; Cyprus. It has been introduced to Australia, North ca. 579 inhabitants). Colonies were located by actively America and South America. The species has also searching the streets of the municipalities (private gar- been recorded from central and eastern Palaearctic dens were not sampled). Nests were observed weekly regions and from India (Schmid-Egger et al., 2017). and the development or decline of each colony was According to Castro & Carbonell Font (2016), nine recorded. Data was obtained by direct observation species of Polistes are present in the Iberian Peninsula. and using a structured questionnaire through face-to- Polistes dominula nests are frequent in urban areas of face interviews with owners, with the aim to describe south-western Spain and, despite their beneficial roles the knowledge, attitudes and practices of inhabit- as pollinators and pest controllers (Sumner et al., ants towards the wasps. Direct observations were 2018), the presence of the wasps alarms people liv- conducted from 10:00 to 13:00 h and from 17:00 to ing near the nests. Numerous media campaigns have 21:00 h with the help of binoculars, so as not to disturb increased interest in this issue and have heightened the the behavior of the wasps or the potential predators. concerns of city inhabitants. This fear, which is not Direct observations were made in areas where poten- always fully justified, prompts people to massively tial predators were previously detected. The causes informs municipal services about practically all of the of colony decline were divided into five categories: observed colonies of wasps. (1) human activities, (2) nest abandonment by found- The aim of this study was to determine the major ress, (3) natural causes (natural colony decline after causes of mortality of P. dominula colonies in the emergence of fertile females and males), (4) pre- urban areas of the south-western Iberian Peninsula. dation, and (5) unknown causes. A nest was consid- Observations were conducted between March and ered abandoned when its construction was interrupted October in 2017 and 2018, in three municipalities of during the first phases of the colony cycle. In these south-western Spain (Badajoz province, Extremadura cases, nests appear with a very low number of cells. region, Spain): Olivenza (38°41′0.6″ N, 7°05′58″ W; Data on nests destroyed by humans were obtained ca. 12000 inhabitants), San Francisco de Olivenza through owner surveys. Where possible, information (38°44′44″ N, 7°06′14″ W; ca. 500 inhabitants) and was also obtained from workers working on the streets

Graellsia, 76(1), junio 2020, e109 — ISSN-L: 0367-5041 – https://doi.org/10.3989/graellsia.2020.v76.261 Notas / Notes 3

(builders, electricians, painters). Predation was quanti- (2011) and Kozyra & Baraniak (2016) also reported fied in two ways: direct observation (ants, vertebrates) cases of ant predation on field colonies of P. nimpha and observation of damage to nests or by detection of (Christ, 1791) and P. gallicus Linnaeus, 1761, respec- remains below nests (see Kozyra & Baraniak, 2016). tively. Direct attacks by the Moorish Gecko (Tarentola In this study we only consider rain as the only natural mauritanica Linnaeus, 1758) were observed in three cause of nest disappearance. In the unknown category cases. This reptile is very common in anthropogenic are included those nests to which we could not attri- habitats of the Iberian Peninsula. They are mostly insec- bute to any of the causes listed above to justify their tivorous and forage widely or adopt an ambush strategy disappearance. These causes can be some of those to obtain prey (Hódar et al., 2006). We suspected that previously mentioned or others, such as parasites, dis- at least six nests were predated by insect-eating birds. eases, lack of food or threats from predators. Specifically, by the Common House Martin (Delichon The number of nests destroyed by humans was urbicum Linnaeus, 1758), an insectivorous migrating 179 (43.55 %). The nests were destroyed by physi- bird that build its nests in roofs and other human arti- cal knock-down (72.62 %) much more often than with facts. On several occasions we saw Common House insecticides, fire (or smoke) or by plugging up the nest Martins feeding near P. dominula nests. In Italy, Cervo (when they are located in cracks) probably due to the & Turillazzi (1985) pointed out that the failure of field fact that, in most cases, the nests are located at 3-4 m colonies of P. nimpha was mainly due to bird predation above the ground. In Piscataway (New Jersey, USA), (60.5 % of the studied cases). Fowler (1983) found that 45 % of the nests of Polistes The causes of mortality of 56 nests were unknown. studied were destroyed by man (of which 64.3 % were We suspect that the unknown causes of mortality were destroyed by treating with pesticides and the remain- mainly climatic conditions (e.g., the extreme tempera- ing 35.7% by knock down). Reed & Vinson (1979) tures in the summer of 2017 and the storms and heavy examined the direct effects of human intervention on rains in the spring of 2018), but we cannot reject the colony survivorship in Texas, finding up to 50 % of factors previously mentioned. Miyano (1980) could the nests were destroyed by humans. not explain the failure in a high percentage of P. chine- Of the 411 nests observed, 83 (20.19 %) were nis antennalis nests and points out that they probably abandoned by their foundress (Fig. 1). The abandon- failed because they lost their queens. In Poland, the ment rate was highest in the first 2-3 weeks (54.21 %) unknown cause of mortality of P. nimpha (Christ, of the colony cycle and slowed down with the appear- 1791) colonies oscillated between 20.4 and 39.4 % ance of the first workers, as previously pointed out (Kozyra & Baraniak, 2016). by Tibbetts & Reeve (2003). Several factors have In terrestrial ecosystems, hymenopterans are one of been mentioned to explain the abandonment of the most seriously threatened insect groups (Sánchez- nests by the foundress of Polistes species: predation Bayo & Wyckhuys, 2019). The main drivers of spe- (Judd, 1998; Kozyra & Baraniak, 2016), parasitism cies declines appear to be in order of importance: 1) (Cervo & Turillazzi, 1985), scarcity of available food habitat loss and conversion to intensive agriculture (Nonacs & Reeve, 1995) and adverse weather condi- and urbanisation; 2) pollution, mainly that by syn- tions (Miyano, 1980). In addition, Tibbetts & Reeve thetic pesticides and fertilizers; 3) biological factors, (2003) found that smaller singly founded nests failed including pathogens and introduced species; and 4) more than larger singly founded nests, thus indicat- climate change. However, in urban habitats man´s ing that the cause of foundress disappearance may direct intervention seems to be a key factor in the be more complicated than foundress death. These decline of hymenopterans, circumstance that may be authors pointed out that perhaps foundresses on small corrected by educational programs. less-successful nests abandon these nests to pursue other reproductive strategies. In this way, Nonacs & Acknowledgements Reeve (1995) found that solitary foundresses readily pursue alternative strategies such as usurping, adopt- We sincerely thank the people of Olivenza, San Francisco de ing or joining other nests. Olivenza and San Benito de la Contienda for help and collabora- Natural causes accounted for 19.95 % of total mor- tion during the fieldwork of this study. tality of P. dominula colonies. Kozyra & Baraniak (2016) found that only 11 of the 308 nests studied References (3.6 %) near Poznan (Poland) showed signs of natural colony decline. This corroborates the fact that in Castro, L. & Carbonell Font, R., 2016. Presencia de urban environments the nests are more protected from Polistes bischoffi (Hymenoptera, Vespidae) en Cataluña adversity than in the countryside. (Península Ibérica). Butlletí de la Institució Catalana Ant predation was detected in two nests. Miyano d’Història Natural, 80: 25–27. (1980) pointed out that ants are a serious threat to P. Cervo, R. & Turillazzi, S., 1985. Associative foundation and chinensis antennalis Pérez, 1905 in Japan, especially nesting sites in Polistes nimpha. Naturwissenschaften, during the early phases of the nesting period. Rusina 72(1): 48–49. https://doi.org/10.1007/BF00405334

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Fowler, H.G., 1983. Human effects on nest survivorship of Reed, H. C. & Vinson, S. B., 1979. Nesting ecology of urban synanthropic wasps. Urban Ecology, 7: 137–143. paper wasps (Polistes) in a Texas urban area (Hymenop- https://doi.org/10.1016/0304-4009(83)90032-3 tera: Vespidae). Journal of the Kansas Entomological Hódar, J., Pleguezuelos, J. M., Villafranca, C. & Fér- Society, 52: 673–689. nandez-Cardenate, J. R., 2006. Foraging mode of Rusina, L. Yu., 2011. Some aspects of interrelations between the moorish gecko Tarentola mauritanica in an arid ants (Hymenoptera, Formicidae) and polistine wasps environment: inferences from abiotic setting, prey (Hymenoptera, Vespidae). Entomological Review, 91: availability and dietary composition. Journal of Arid 241–252. https://doi.org/10.1134/S0013873811020126 Environments, 65: 83–93. https://doi.org/10.1016/j. Sánchez-Bayo, F. & Wyckhuys, K. A. G., 2019. World- jaridenv.2005.08.006 wide decline of the entomofauna: A review of its driv- Judd, T. M., 1998. Defensive behavior of colonies of the ers. Biological Conservation, 232: 8–27. https://doi. paper wasps, Polistes fuscatus, against vertebrate org/10.1016/j.biocon.2019.01.020 predators over the colony cycle. Insectes Sociaux, 45: Schmid-Egger, C., van Achterberg, K., Neumeyer, R., 197–208. https://doi.org/10.1007/s000400050080 Morinière, J. & Schmidt, S., 2017. Revision of the West Kozyra, K. B. & Baraniak, E., 2016. Causes of mortal- Palaearctic Polistes Latreille, with the descriptions of two ity of Polistes nimpha colonies. Insectes Sociaux, 63: species – an integrative approach using morphology and 481–482. https://doi.org/10.1007/s00040-016-0484-0 DNA barcodes (Hymenoptera, Vespidae). ZooKeys, 713: Miyano, S., 1980. Life tables of colonies and workers in 53–112. https://doi.org/10.3897/zookeys.713.11335 a paper wasp, Polistes chinensis antennalis, in Central Sumner, S., Law, G. & Cini, A., 2018. Why love bees and Japan (Hymenoptera: Vespidae). Researches on Popu- hate wasps. Ecological Entomology, 43: 836–845. lation Ecology, 22: 69–88. https://doi.org/10.1007/ https://doi.org/10.1111/een.12676 BF02513536 Tibbetts, E. A. & Reeve, H. K., 2003. Benefits of found- Nonacs, P. & Reeve, H. K., 1995. The ecology of coopera- ress associations in the paper wasp Polistes dominulus: tion in wasps: causes and consequences of alternative increased productivity and survival, but no assurance reproductive decisions. Ecology, 76: 953–967. https:// of fitness returns. Behavioral Ecology, 14(4): 510–514. doi.org/10.2307/1939359 https://doi.org/10.1093/beheco/arg037

Graellsia, 76(1), junio 2020, e109 — ISSN-L: 0367-5041 – https://doi.org/10.3989/graellsia.2020.v76.261